JP2023003968A - Communication cable - Google Patents

Abstract

To provide a communication cable capable of preventing a formation of a crack potentially leading to a deterioration of shield performance, in a film-like noise shield material having a metal layer.SOLUTION: A communication cable 1 includes: a core wire 2 having a conductor 21 and an insulator layer 22 surrounding an outer periphery of the conductor 21; and a film-like shield 3 attached surrounding an outer periphery of the core wire 2 in a longitudinal direction. The film-like shield 3 includes: a metal matrix layer 32 composed of a metal layer; and a stripe member 33 being a linear or belt-like component closely adhered onto the metal matrix layer 32. The stripe member 33 is extended along an axial direction A1 of the core wire 2, and a plurality of the stripe members are arranged with intervals along a circumferential direction A2 of the core wire.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to communication wires.

Copper, aluminum, or their metals are used around the outer circumference of the core wire as a noise shielding layer to reduce the intrusion of noise from the outside and the emission of noise to the outside in communication wires used in fields such as automobiles. In some cases, a shield body having a metal layer made of an alloy or the like containing the metal is arranged. For example, Patent Literature 1 discloses a communication wire provided with a metal foil shield.

JP 2009-146850 A Japanese Utility Model Laid-Open No. 03-112828 JP-A-2002-329425 Japanese Utility Model Laid-Open No. 63-146913 Japanese Utility Model Laid-Open No. 05-090739

In an electric wire for communication, it is easier to obtain high shielding performance by arranging a film-shaped shield having a metal layer in a tandem arrangement rather than by arranging it in a horizontal winding form. However, when a tandem film shield is used, cracks may be formed in the metal layer of the film shield when the communication wire is repeatedly bent. Since bending is to bend the communication wire in the axial direction, in the film shield, cracks in the metal layer are likely to be formed in a direction intersecting the axial direction, that is, a direction perpendicular to the axial direction or a direction close to it. If cracks are formed in the metal layer of the film-like shield, the shielding performance may be degraded and noise may not be sufficiently shielded.

Especially in the field of automobiles, with the development of automatic driving technology, there is a demand for communication wires capable of transmitting a large amount of information at high speed, such as information necessary for recognizing images outside the vehicle. As the speed of communication increases, the influence of noise becomes more serious, so it is desired to impart high shielding performance to communication wires. Therefore, in the film shield, it is preferable to suppress the formation of cracks due to bending as described above. However, wires routed in a portion subjected to repeated bending, such as the inside of an automobile door, may develop cracks in the film shield in a direction intersecting the axial direction of the communication wire due to the bending. in a comfortable environment.

In view of the above, it is an object of the present invention to provide a communication wire in which the formation of cracks, which leads to a decrease in shielding performance, is suppressed in a film-shaped noise shield material having a metal layer.

A communication wire according to the present disclosure includes a core wire having a conductor, an insulating layer covering the outer circumference of the conductor, and a film-like shield surrounding the outer circumference of the core wire in a tandem manner, The film-like shield has a metal base layer composed of a metal layer and a striped material that is a linear or band-like member that is in close contact with the metal base layer, and the striped material extends along the axial direction of the core wire. and a plurality thereof are arranged at intervals along the circumferential direction of the core wire.

The communication wire according to the present disclosure is a communication wire in which the formation of cracks that lead to deterioration of the shielding performance is suppressed in the film-shaped noise shield material having the metal layer.

1A and 1B are a perspective view and a cross-sectional view showing a communication wire according to a first embodiment of the present disclosure; FIG. FIG. 2 is a perspective view showing the configuration of a film shield included in the communication wire according to the first embodiment. 3A and 3B are a perspective view and a cross-sectional view showing a communication wire according to a second embodiment of the present disclosure; FIG. FIG. 4 is a perspective view showing the configuration of a film shield included in the communication wire according to the second embodiment. 5A to 5C are side views showing configurations of communication wires used for evaluation of shield performance, in which directions of slits formed in the film-like shield are different. The slits are parallel to the axial direction of the core wire in sample A of FIG. 5A, oblique (45°) in sample B of FIG. 5B, and perpendicular to sample C of FIG. 5C. FIG. 6 is a diagram showing results of evaluating the shielding performance of four types of communication wires.

[Description of Embodiments of the Present Disclosure]
First, embodiments of the present disclosure will be described.
A communication wire according to the present disclosure includes a core wire having a conductor, an insulating layer covering the outer circumference of the conductor, and a film-like shield surrounding the outer circumference of the core wire in a tandem manner, The film-like shield has a metal base layer composed of a metal layer and a striped material that is a linear or band-like member that is in close contact with the metal base layer, and the striped material extends along the axial direction of the core wire. and a plurality thereof are arranged at intervals along the circumferential direction of the core wire.

In the above-mentioned communication wire, the film-like shield arranged on the outer periphery of the core wire has a metal base layer, so that it functions as an electromagnetic wave shield, preventing noise from entering the core wire and emitting noise from the core wire. Suppress. A plurality of striped members configured as linear or strip-shaped members are closely attached to the surface of the metal base layer of the film-like shield and are provided along the circumferential direction of the core wire, thereby forming the metal base layer of the film-like shield. Furthermore, cracks extending in a direction crossing the axial direction of the core wire are less likely to be formed. Moreover, even if a crack is formed in a direction intersecting the axial direction, the crack is formed only as a short crack. To maintain high shielding performance of a communication wire even in an environment where it is susceptible to bending, such as inside an automobile, by preventing the formation of long cracks in a direction intersecting the axial direction even when the communication wire is repeatedly bent. can be done. Even if cracks are formed in the metal base layer of the film-like shield during bending, the cracks tend to occur along the axial direction of the core wire. Even if a crack extending along the axial direction is formed, it is less likely to lead to a significant deterioration in the shielding performance of the communication wire compared to a crack extending in a direction intersecting the axial direction.

Here, the communication electric wire is configured as a coaxial electric wire, and preferably further includes a braided shield that surrounds the outer side of the film shield and is made of a braided body of metal wires. Due to its structure, coaxial wires are susceptible to noise, but by providing the above-mentioned film-like shield around the core wire, it has high shielding performance and maintains its high shielding performance even after repeated bending. can do. Furthermore, the provision of the braided shield in addition to the film shield enhances the shielding performance.

The stripe material is preferably made of a material containing an organic polymer. Then, it is possible to easily form a film shield having a striped material using a lightweight and inexpensive material. Furthermore, when the braided shield is arranged adjacent to the film-like shield, the metal base layer comes into contact with the braided shield through the organic polymer layer constituting the stripe material at the location where the stripe material is arranged. Therefore, the stripe material has a cushioning function, and when the communication wire is bent, a large load is less likely to be applied from the braided shield to the surface of the metal base layer, and the bending resistance of the communication wire is enhanced.

In this case, the stripe material is preferably made of a material containing a conductive polymer. Then, in the film-like shield, the entire surface on which the metal base layer and the stripe material are arranged becomes conductive, and high shielding performance can be obtained. In addition, it is easy to ensure conduction between a film-like shield such as a braided shield and a conductive member that is placed in an overlapping manner.

Alternatively, the striped material may be composed of metal wires or conductive fibers. Then, since the striped material has high material strength, the mechanical strength of the film shield can be increased. Moreover, even if a crack is formed in the metal base layer, the conductive stripe material can function as a path through which the return current flows, so that high shielding properties can be maintained.

The film shield may further have a metal coating layer as a metal layer different from the metal base layer, and the striped material may be sandwiched between the metal base layer and the metal coating layer. Then, on the surface of the metal base layer, it is easy to maintain the stripe material in the state of being extended along the axial direction of the core wire and in the state of being arranged at predetermined intervals. In addition to the metal base layer, the metal coating layer also functions as a shield body and contributes to the improvement of the shield performance.

The film-like shield further has a sheet-like polymer base material containing an organic polymer, the metal base layer is formed on the surface of the polymer base material, and the metal base layer has , the stripe material may be arranged. By using a polymer base material, the metal base layer can be formed as a metal thin film, and can be easily held stably. In addition, the strength and handleability of the film-like shield as a whole can be enhanced.

In this case, the communication wire is composed of a braided body of metal wires, and has a braided shield surrounding the outer periphery of the core wire, and the film-like shield is arranged with the polymer base material. contact with the braided shield on the opposite side. By arranging the braided shield in addition to the film-like shield in the communication wire, the shielding characteristics can be effectively improved. At this time, in the film-like shield, the side opposite to the polymer substrate, that is, the side where the stripe material is arranged on the surface of the metal base layer, or the side where the metal coating layer is arranged is brought into contact with the braided shield. By doing so, conduction can be ensured between the film-like shield and the braided shield.

[Details of the embodiment of the present disclosure]
A communication wire according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. Hereinafter, the terms such as parallel, perpendicular, etc. that express the shape and arrangement of members include not only geometrically strict concepts but also the range of errors that are generally permitted in communication wires. For example, it is assumed that the angle includes an error of about ±10°.

[1] Communication Wire According to First Embodiment FIGS. 1A and 1B show the structure of a communication wire 1 according to the first embodiment of the present disclosure. 1A is a perspective view, and FIG. 1B is a cross-sectional view cut perpendicularly to the axial direction.

(Overall configuration of communication wire)
The communication wire 1 is configured as a coaxial wire. Specifically, the communication wire 1 includes a core wire 2 having a conductor 21 and an insulating layer 22 covering the outer circumference of the conductor 21 . A film shield 3 is provided around the core wire 2 . A braided shield 4 configured as a braided body in which metal wires are woven is provided on the outer circumference of the film-like shield 3 . Furthermore, a sheath layer 5 is provided on the outer circumference of the braided shield 4 .

The communication wire 1 as described above, which is configured as a coaxial wire having a film-like shield 3 and a braided shield 4 around the core wire 2, is suitable for transmitting signals in a high frequency range of 1 GHz or higher. be able to. However, the communication wire 1 according to the present disclosure is not limited to having the above structure as long as it surrounds the core wire 2 and is provided with the film shield 3. A configuration corresponding to the For example, in the above embodiment, an insulated wire including the conductor 21 and the covering layer 22 is used alone as the core wire 2, but a plurality of insulated wires may be used. Specifically, the core wire 2 can be configured such that a pair of insulated wires are twisted together or run in parallel to transmit a differential signal. Moreover, the braided shield 4 may be omitted when the influence of noise is not so great. Furthermore, in the above embodiment, each of the layers described above is formed in direct contact with the outer periphery of the inner constituent layer, but the communication wire 1 may appropriately include constituent layers other than the layers described above. may be Each constituent member of the coaxial communication wire 1 exemplified above will be described below.

The core wire 2 is a signal wire for transmitting electric signals in the communication wire 1 and has a conductor 21 and an insulating layer 22 covering the outer periphery of the conductor 21 . The material forming the conductor 21 and the insulating layer 22 is not particularly limited. Various metal materials can be used as the material for the conductor 21, but copper or a copper alloy is preferably used because of its high conductivity. Although the conductor 21 may be configured as a single wire, it is preferably configured as a twisted wire in which a plurality of strands (for example, seven wires) are twisted together from the viewpoint of increasing flexibility when bending. The insulating layer 22 insulates the conductor 21 in the core wire 2 and is made of a material containing an organic polymer. The type of organic polymer is not particularly limited, and examples include olefin polymers such as polyolefins and olefin copolymers, halogen polymers such as polyvinyl chloride, various engineering plastics, elastomers, and rubbers. The insulating layer 22 may contain additives as appropriate in addition to the organic polymer.

The film-like shield 3, which will be described in detail later, is constructed as a composite in which a polymer base 31, a metal base layer 32, and a plurality of rows of striped materials 33 are laminated. The film shield 3 functions as a noise shield member by having the metal base layer 32 . In other words, an external electromagnetic wave enters the core wire 2 and causes noise in the signal transmitted through the core wire 2, and the electromagnetic wave generated by the signal transmitted through the core wire 2 is released to the outside and becomes a noise source. suppress

The film-like shield 3 is arranged on the outer circumference of the core wire 2 in a tandem manner. That is, along the circumferential direction of the core wire 2 , the film-like shield 3 is arranged so that the surface of the film-like shield 3 wraps around the outer circumference of the core wire 2 . By arranging the film-like shield 3 in a vertical manner, high shielding performance can be achieved compared to a form in which the film-like shield 3 is arranged in a horizontal winding form (a form in which a tape-shaped film-like shield is spirally wound around the outer periphery of the core wire 2). can get.

The direction of the front and back when the film-like shield 3 is arranged around the core wire 2 is not limited. The film shield 3 is preferably arranged so that it contacts the braided shield 4 on the opposite side. That is, the surface of the metal base layer 32 on which the striped material 33 is arranged may be directed toward the braided shield 4 . In the illustrated embodiment, the surface of the polymer base material 31 may be directed inward, and the surface of the metal base layer 32 on which the striped material 33 is arranged may be directed outward. As a result, electrical continuity with the braided shield 4 can be ensured at the portion of the surface of the metal base layer 32 that is not covered with the stripe material 33 and is exposed.

The braided shield 4 is configured as a braided body in which a plurality of metal wires are woven together to form a hollow tubular shape. Examples of the metal wires forming the braided shield 4 include metal materials such as copper, copper alloys, aluminum, and aluminum alloys, and metal materials whose surfaces are plated with tin or the like. In the communication wire 1, the braided shield 4 is not necessarily provided, but by providing it, together with the metal base layer 32 of the film-like shield 3, it functions as a noise shield member. The braided shield 4 may be provided outside or inside the film shield 3, but as shown in the figure, it is preferable to provide it outside from the viewpoint of reducing signal loss.

The sheath layer 5 is arranged as the outermost layer of the communication wire 1 and serves to protect the core wire 2, the film shield 3, and the braided shield 4 arranged inside. The sheath layer 5 is made of a material containing an organic polymer. The type of organic polymer is not particularly limited, and examples include olefin polymers such as polyolefins and olefin copolymers, halogen polymers such as polyvinyl chloride, various engineering plastics, elastomers, and rubbers. The sheath layer 5 may contain additives as appropriate in addition to the organic polymer. Furthermore, the sheath layer 5 may contain a powdered magnetic material, especially a soft magnetic material. Then, in the communication wire 1, the sheath layer 5 functions as a noise shield together with the film shield 3 and the braided shield 4. FIG. Examples of soft magnetic materials include metal oxides such as ferrite, iron (pure iron or iron containing a small amount of carbon), various magnetic stainless steels, and alloys such as Fe—Ni alloys (permalloy).

(Details of film shield)
As shown in the overall diagrams of the communication wire 1 in FIGS. 1A and 1B, and as the structure of the film shield 3 is shown in a perspective view in FIG. It is configured as a composite having a base layer 32 and rows of a plurality of striped materials 33 laminated in this order.

The polymer base material 31 is a sheet-like member made of a material containing an organic polymer. The polymer base material 31 is not necessarily provided on the film shield 3, but by using the polymer base material 31, the metal base layer 32 as a thin metal layer can be easily formed and stably held. can be done. In addition, the mechanical strength and handleability of the film shield 3 can be enhanced. The organic polymer that constitutes the polymer base material 31 is not particularly limited, but examples thereof include polyolefins such as polyethylene terephthalate (PET) and polypropylene (PP), and polyvinyl chloride (PVC). In particular, PET can be preferably used from the viewpoint of high mechanical strength. The polymer base material 31 may appropriately contain various additives in addition to the organic polymer.

The metal base layer 32 is configured as a continuous metal layer covering one surface of the polymer base material 31, and serves as a shielding member that shields electromagnetic noise by electrostatic shielding in the communication wire 1. The type of metal constituting the metal base layer 32 is not particularly limited, but metals commonly used as shielding materials such as copper, copper alloys, aluminum, aluminum alloys, silver, silver alloys, gold, gold alloys, etc. can be suitably used also in this embodiment. In particular, it is preferable to use copper or a copper alloy. A plurality of metal material layers may be stacked to form the metal base layer 32 . The metal base layer 32 is integrally bonded to the surface of the polymer base material 31 by vapor deposition, plating, adhesion, or the like.

The stripe material 33 is configured as a linear or belt-like member. In the film-like shield 3 , a plurality of striped materials 33 are arranged in close contact with the surface of the metal base layer 32 , that is, the surface of the metal base layer 32 opposite to the surface in contact with the polymer base 31 . Here, with respect to the striped material 33, being linear or band-like refers to a shape in which the dimension in the width direction (direction A2) is smaller than the dimension in the longitudinal direction (direction A1). In the case of a linear shape, the dimension in the thickness direction is equal to or larger than the dimension in the width direction, and in the case of a strip shape, the dimension in the thickness direction is smaller than the dimension in the width direction. In the first embodiment, it is particularly preferable that the striped material 33 is a band-shaped member.

The material of the striped material 33 is not particularly limited as long as it is configured as a linear or strip-shaped member, but it is preferable that the striped material 33 has a higher bending resistance than the constituent material of the metal base layer 32. . In other words, it is preferable to form the stripe member 33 using a material that is less likely to cause damage such as cracks or breaks than the metal base layer 32 when the communication wire 1 is bent.

In the communication wire 1 according to the first embodiment, the striped material 33 is made of a material containing an organic polymer. Preferably, the stripe material 33 is mainly composed of an organic polymer. The organic polymer forming the stripe material 33 is not particularly limited, but examples include polyolefins such as PET and PP, thermoplastic resins such as PVC, and various curable resins. In particular, PET can be preferably used from the viewpoint of high mechanical strength. The stripe material 33 may appropriately contain various additives in addition to the organic polymer. Furthermore, it is preferable that the stripe material 33 is made of a material containing a conductive polymer and has conductivity as a whole. In this case, the material composing the stripe material 33 may be an organic polymer itself made of a conductive polymer, or may be made conductive by mixing various organic polymers with a conductive additive. good. The plurality of stripe materials 33 may all be made of the same material, or may be mixed with a plurality of stripe materials 33 having different constituent materials.

The striped material 33 extends along the axial direction of the core wire 2 (longitudinal direction in which the core wire 2 extends) A1 on the surface of the metal base layer 32 . A plurality of striped members 33 are arranged at intervals in the circumferential direction A2 of the core wire 2, that is, along the direction orthogonal to the axial direction A1. The plurality of stripe members 33 are parallel to each other.

In the film-like shield 3, a plurality of striped materials 33 are arranged on the surface of the metal base layer 32 along the axial direction A1 of the core wire 2, so that the metal base layer 32 crosses the place where the striped materials 33 are arranged. Cracks are less likely to occur. This is because the presence of the striped material 33 prevents the generation and propagation of cracks. Therefore, in the metal base layer 32, formation of cracks extending in a direction crossing the axial direction A1 of the core wire 2, that is, a direction A2 perpendicular to the axial direction A1 or a direction close thereto is less likely to occur. Moreover, even if a crack extending in the direction intersecting with the axial direction A1 is formed, the crack is suppressed to be short.

If the striped material 33 were not arranged on the surface of the metal base layer 32, cracks would easily occur in the metal base layer 32 at the bent portions when the communication wire was subjected to repeated bending. Since bending occurs along the axial direction A1 of the core wire 2, the metal base layer 32 is applied with a force in the direction of bending and stretching along the axial direction A1. Directional cracks are likely to occur. Cracks generated in the metal base layer 32 deteriorate the shielding performance of the film shield 3 . In particular, the more the crack extends in the direction A2 perpendicular to the axial direction A1 or in a direction close to it, the more markedly the shielding performance is degraded. This is because the path of the return current that flows along the axial direction A1 on the surface of the metal base layer 32 is cut off by the crack, and the return current flows around the crack, making it impossible to cancel out the noise. In recent years, communication wires installed in automobiles are required to have high noise shielding performance due to the increase in frequency. Since it is frequently subjected to loads in the direction of bending in the axial direction, cracks intersecting with the axial direction, which is a factor of deteriorating the noise shielding property, are likely to occur.

On the other hand, in the communication wire 1 according to the present embodiment, even if it is repeatedly bent, the striped material 33 is arranged on the metal base layer 32 of the film-like shield 3, so that the striped material 33 is crossed. Since cracks extending in the direction intersecting with the axial direction A1 are less likely to occur, high shielding performance is maintained over a long period of time even in environments subject to bending. Therefore, the communication wire 1 according to the present embodiment can be suitably used in places such as the inside of automobiles, which are likely to receive loads in the bending direction and where high noise shielding properties are required.

In the film-like shield 3, cracks extending in a direction along the axial direction A1 of the core wire 2, that is, in a direction parallel to the axial direction A1 or in a direction close thereto are not formed in the metal base layer 32 even if the stripe material 33 is provided. However, cracks along the axial direction A1 do not reduce the shielding performance of the metal base layer 32 as much as cracks transverse to the axial direction A1, as will be shown in later examples. This is because cracks along the axial direction A1 are less likely to have a large effect on the path of the return current flowing through the metal base layer 32 . When the communication wire 1 is repeatedly bent, cracks are formed in the metal base layer 32, so that the stress applied to the metal base layer 32 can be relaxed. Therefore, in the metal base layer 32 of the film-like shield 3, the presence of the striped material 33 during bending suppresses the formation of cracks in the metal base layer 32 in the direction intersecting the axial direction A1, and If cracks are formed, stress relaxation can reduce the mechanical load associated with bending in the metal base layer 32 while avoiding a significant deterioration in shielding performance due to crack formation.

Furthermore, in the communication wire 1 according to the present embodiment, the striped material 33 provided on the film shield 3 is made of a material containing an organic polymer, thereby suppressing deterioration in shield performance due to bending. In addition, the resistance to bending of the communication wire 1 is enhanced by reducing the load applied to the film shield 3 from adjacent members due to bending. Specifically, the organic polymer layer of the striped material 33 is interposed between the metal base layer 32 and the braided shield 4, so that the striped material 33 exhibits a buffering function. In other words, the load that the metal base layer 32 receives when the metal base layer 32 is bent from the braided shield 4 due to contact with the braided shield 4 and the distortion of the metal base layer 32 due to the load are alleviated by the interposition of the stripe material 33 configured as an organic polymer layer, The metal base layer 32 is less likely to be deformed excessively and damaged such as cracks due to bending.

In the film shield 3, from the viewpoint of efficiently suppressing the formation of cracks crossing the axial direction A1 by the stripe material 33 and from the viewpoint of obtaining the effect at each position in the circumferential direction A2, the arrangement interval d1 of the stripe material 33 is , 1 mm or less in length, and 15% or less of the circumferential length (the length of a straight line that circles the surface of the metal base layer 32 along the circumferential direction A2 of the core wire 2). The smaller the arrangement interval d1 of the stripe members 33, the higher the effect of suppressing cracks. From the viewpoint of simplification, the arrangement interval d1 is preferably 0.4 mm or more in length and 5% or more of the circumference. The stripe material 33 does not necessarily have to be arranged at equal intervals along the circumferential direction A2, but from the viewpoint of obtaining the same crack suppression effect at each position in the circumferential direction A2, the error is within about ±10%. It is preferable to arrange them at regular intervals.

Of the area of the entire surface of the metal base layer 32, the coverage, which is the area of the region where the stripe material 33 is provided (the area of the region covered with the stripe material 33), effectively prevents the formation of cracks crossing the axial direction A1. From the viewpoint of suppression, it is preferably 40% or more. On the other hand, the surface of the metal base layer 32 that is not covered with the stripe material 33 preferably has a coverage of 80% or less from the viewpoint of sufficiently ensuring electrical connection with the braided shield 4 . If the striped material 33 contains a conductive polymer and exhibits conductivity as a whole, it is possible to obtain electrical continuity with the braided shield 4 even at locations covered with the striped material 33 .

The method of adhering the stripe material 33 containing an organic polymer to the surface of the metal base layer 32 is not particularly limited, but it is preferable to use adhesion. In this case, when the constituent material of the striped material 33 itself is made of a thermoplastic resin or various hardening resins exhibiting adhesiveness to the metal base layer 32, the liquid resin material is applied to the metal base layer 32 in a predetermined striped pattern. The stripe material 33 may be formed by placing it on the surface of the base layer 32 and then solidifying it. On the other hand, when the constituent material of the stripe material 33 itself does not exhibit adhesiveness to the metal base layer 32, or when it is difficult to dispose on the surface of the metal base layer 32 in a liquid state, etc., the structure of the stripe material 33 The striped material 33 may be adhered to the surface of the metal base layer 32 by using an adhesive agent or pressure-sensitive adhesive that is different from the material. When the stripe material 33 contains a conductive polymer and exhibits conductivity as a whole, it is preferable to use a conductive adhesive or pressure-sensitive adhesive. When the striped material 33 is adhered to the surface of the metal base material 32 using an adhesive or adhesive, the striped material 33 is arranged parallel to each other with a predetermined interval for the purpose of improving the handleability of the striped material 33 . The adjacent striped members 33 may be connected by crossing members arranged to intersect the direction in which the striped members 33 extend (axial direction A1). From the standpoint of facilitating the formation of cracks along the line and the standpoint of facilitating ensuring electrical continuity between the metal base layer 32 and the braided shield 4, the area occupied by the cross member on the surface of the metal base layer 32 is reduced by the stripe material 33. It is preferable to keep it to 20% or less of the area occupied.

In addition, in the film-shaped shield 3 that constitutes the communication wire 1 according to the first embodiment, from the viewpoint of structural simplicity and lightness, is preferably free of other layers. However, similarly to the film-shaped shield 3' that constitutes the communication wire 1' according to the second embodiment of the present disclosure described below, the metal coating layer 35 is formed on the surface of the metal base layer 32 provided with the stripe material 33. may be provided to sandwich the stripe material 33 between the metal base layer 32 and the metal coating layer 35 .

[2] Communication wire according to second embodiment Next, a communication wire according to a second embodiment of the present disclosure will be described. 3A and 3B show the structure of a communication wire 1' according to a second embodiment of the present disclosure. 3A is a perspective view, and FIG. 3B is a cross-sectional view cut perpendicularly to the axial direction. Moreover, FIG. 4 shows a perspective view of the structure of a film shield 3' included in the communication wire 1' according to the second embodiment. Hereinafter, configurations common to those of the communication wire 1 according to the first embodiment are denoted by corresponding reference numerals in the drawings, and descriptions thereof are omitted.

A communication wire 1' according to the second embodiment has a configuration similar to that of the communication wire 1 according to the first embodiment, but a film shield 3 having a configuration different from that of the first embodiment. '. The film shield 3' of the communication wire 1' according to the second embodiment is configured as a composite in which a polymer substrate 31, a metal base layer 32, a stripe material 34, and a metal coating layer 35 are laminated in this order. Of these, the polymer substrate 31 and the metal coating layer 35 are optional components, but are preferably provided. When the polymer substrate 31 is provided, in the communication wire 1', the film-like shield 3' is provided with the stripe material 34 and the metal coating layer 35 on the opposite side of the polymer substrate 31. It is placed in contact with the braided shield 4 on the side that is covered.

In the film shield 3' of the second embodiment, the polymer substrate 31 and the metal base layer 32 may be the same as those of the film shield 3 of the first embodiment. However, the stripe material 34 is configured as a conductive linear member in this embodiment. More specifically, the striped material 34 is composed of metal wires or conductive fibers. The specific constituent material of the stripe material 34 is not particularly limited, but in the case of metal wires, metal materials such as copper, copper alloys, aluminum, and aluminum alloys, or tin or the like is added to the surface of these metal materials. It is possible to preferably use those plated by. The metal wire may be a single wire or a twisted wire, but is preferably a single wire from the viewpoint of ensuring a small diameter. On the other hand, when the stripe material 34 is a conductive fiber, the composition is not particularly limited as long as it is a flexible wire other than a metal wire. Examples include a fibrous material obtained by mixing the powder of the conductive substance in (1), and an organic polymer fiber provided with a metal layer on the outer periphery thereof.

The metal coating layer 35 is configured as a continuous metal layer and serves to adhere the stripe material 34 to the metal base layer 32 . The metal coating layer 35 also functions as a noise shield material together with the metal base layer 32 . Similarly to the metal base layer 32, copper, copper alloys, aluminum, aluminum alloys, silver, silver alloys, gold, gold alloys, and the like can be suitably used as materials for the metal coating layer 35 as well. In particular, it is preferable to use copper or a copper alloy. Like the metal base layer 32, the metal coating layer 35 may also be combined with a base material made of an organic polymer. and the braided shield 4, the metal coating layer 35 is preferably configured as an independent metal foil that is not combined with the base material.

In the film-like shield 3 ′, the linear striped material 34 is sandwiched between the metal base layer 32 and the metal coating layer 35 and adheres to the metal base layer 32 . In addition to or instead of sandwiching by the metal coating layer 35, the stripe material 34 may be adhered to the surface of the metal base layer 32 via an adhesive or adhesive. In this case, it is preferable that the adhesive and the pressure-sensitive adhesive also have conductivity. Also, the stripe material 34 may be adhered to the metal coating layer 35 in addition to the metal base layer 32 . The metal base layer 32 and the metal coating layer 35 may be bonded to each other at locations where the stripe material 34 is not arranged.

In the present embodiment, as in the first embodiment, a plurality of striped members 34 are arranged along the axial direction A1 of the core wire 2 in the film shield 3', so that the communication wire 1 ' may be bent, the formation of cracks crossing the axial direction A1 on the surface of the metal base layer 32 is suppressed, and even if cracks crossing the axial direction A1 are formed, Short cracks can be suppressed. As a result, even if the communication wire 1' is repeatedly bent, high shielding performance is maintained. In addition, since the stripe material 34 is made of a conductive material, even if a crack is formed in the metal base layer 32 due to bending or the like, the stripe material 34 functions as a return current path. By doing so, the shielding performance of the film-like shield 3' as a whole can be maintained. Furthermore, since the striped material 34 has high material strength, the striped material 34 also functions as a reinforcing material and plays a role in increasing the mechanical strength of the film shield 3'. In particular, when the stripe material 34 is composed of metal wires, it can effectively serve as a return path and as a reinforcing material.

Also in this embodiment, from the same viewpoint as in the first embodiment, in the film shield 3', the arrangement interval d1 of the stripe material 34 is 1 mm or less in length and 15% or less of the circumference. is preferred. On the other hand, although there is no particular lower limit to the arrangement interval d1 of the stripe members 34, it is preferable to set the length to 0.4 mm or more, or 5% or more of the circumferential length, for example. The stripe members 34 do not necessarily have to be arranged at equal intervals along the circumferential direction A2, but are preferably arranged at equal intervals with an error of about ±10%. Moreover, from the viewpoint of obtaining a sufficient crack suppressing effect and a function as a reinforcing material, the wire diameter of the stripe material 34 is preferably 0.6 mm or more. On the other hand, from the viewpoint of ensuring sufficient flexibility, the wire diameter of the stripe material 34 is preferably 0.1 mm or less. Also in the present embodiment, the adjacent striped members 34 arranged parallel to each other with a predetermined interval may be connected by crossing members, but the crossing members are not formed on the surface of the metal base layer 32 . The area occupied by the stripe material 34 should be suppressed to 20% or less of the area occupied by the stripe material 34 .

Examples are shown below. However, the present invention is not limited to these examples. Here, the relationship between the direction of cracks formed in the metal base layer of the film shield and the effect on the shield performance was investigated.

(Preparation of sample)
As samples A to D, four types of coaxial communication wires were prepared. For all four types, a film-like shield, a braided shield, and a sheath layer were arranged in this order on the outer periphery of a core wire in which the outer periphery of a conductor (conductor cross-sectional area: 0.61 mm ² ) was covered with an insulating layer. As the film shield, a PET substrate (thickness: 12 μm) was integrally bonded to a copper metal base layer (thickness: 9 μm) on one side. Placed around the line.

The communication wires of Samples A to D are different from each other in the presence or absence of slits in the film-like shield and the arrangement angle. As shown in FIGS. 5A to 5C, in samples A to C, a slit was formed as a crack model on the surface of the metal base layer of the film shield. In any sample, the slit was formed as an opening penetrating through the metal substrate and the PET substrate in the thickness direction. The length of the slit (d2 in the figure) was set to 1 mm, and the width was set to the minimum workable value. Samples A to C differ from each other in the arrangement angle of the slits. Sample A is arranged parallel to the axial direction of the core wire, Sample B is arranged obliquely at an angle of 45° to the axial direction of the core wire, and Sample C is arranged. In , the arrangement was made perpendicular to the axial direction of the core wire. The slit interval (d3 in the figure) was 2 mm for all samples. For sample D, the film-like shield was not provided with slits for reference.

(Test method)
Each communication wire of Samples A to D was cut to a length of 1200 mm, and shielding attenuation was measured in a region up to 3 GHz. The measurement was performed by a test method based on IEC 62153-4-4.

(Test results)
FIG. 6 shows the measurement results of shielding attenuation for samples AD. The horizontal axis indicates the measurement frequency, and the vertical axis indicates the shielding attenuation (unit: dB). The lower the measured value at each frequency on the vertical axis, the higher the shielding performance.

According to FIG. 6, the highest shielding performance is obtained in the sample D in which the slits are not formed in the film-like shield. Sample A, in which slits were formed parallel to the axial direction of the core wire, had lower shielding performance than Sample D, in which no slits were formed, but the amount of the reduction was slight. In particular, in the region of frequencies higher than about 2 GHz, the shielding attenuation amount is almost the same as that of the sample D. On the other hand, in the samples B and C in which the slits are formed at an angle with respect to the axial direction, the shielding performance is significantly lower than that of the sample D. In particular, Sample C, in which the slits are formed perpendicular to the axial direction, exhibits a marked decrease in shielding performance.

From the above, when a slit is formed in the metal base layer in a film-shaped shield arranged on a communication wire, the closer the extending direction of the slit is to the direction perpendicular to the axial direction of the core wire, the greater the decrease in shielding performance. I know it will be. If the direction in which the slit extends is parallel to the axial direction, even if the slit is formed, the effect on the shielding performance can be minimized. In particular, in a high-frequency region, the effect on shielding performance is reduced, and high shielding performance is maintained despite the formation of slits.

The present invention is by no means limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

1, 1' communication wire 2 core wire 21 conductor 22 insulating layer 3, 3' film shield 31 polymer substrate 32 metal base layer 33, 34 stripe material 35 metal coating layer 4 braided shield 5 sheath layer A1 core wire axial direction A2 Circumferential direction of core wire d1 Arrangement interval of stripe material d2 Slit length d3 Slit interval

Claims (8)

a core wire having a conductor and an insulating layer covering the outer periphery of the conductor;
a film-shaped shield that surrounds the outer periphery of the core wire in a tandem manner,
The film-like shield is
a metal base layer composed of a metal layer;
and a striped material, which is a linear or strip-shaped member in close contact with the metal base layer,
The wire for communication, wherein the stripe material extends along the axial direction of the core wire, and a plurality of the stripe materials are arranged at intervals along the circumferential direction of the core wire. The communication wire is configured as a coaxial wire,
2. The electric wire for communication according to claim 1, further comprising a braided shield made of a braided body of metal wires surrounding the outside of said film-like shield. 3. The communication wire according to claim 1, wherein said stripe material is made of a material containing an organic polymer. 4. The communication wire according to claim 3, wherein said stripe material is made of a material containing a conductive polymer. 3. The electric wire for communication according to claim 1, wherein said striped material is composed of a metal wire or a conductive fiber. The film-like shield further has a metal coating layer as a metal layer different from the metal base layer,
6. The communication wire according to claim 1, wherein said striped material is sandwiched between said metal base layer and said metal covering layer. The film-like shield further has a sheet-like polymer base material containing an organic polymer,
The metal base layer is formed on the surface of the polymer base,
The communication wire according to any one of claims 1 to 6, wherein the striped material is arranged on the surface of the metal base layer opposite to the polymer base material. The communication wire is composed of a braided body of metal wires and has a braided shield surrounding the outer circumference of the core wire,
8. The telecommunication wire of claim 7, wherein the filmy shield contacts the braided shield on the side opposite to where the polymeric substrate is located.

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